"KRON-TV, virtual channel 4 (digital channel 38), is a television station in San Francisco, California, serving as the Bay Area affiliate of the MyNetworkTV programming service; the station is owned by Young Broadcasting. The station's studios are located in the Western Addition section of downtown San Francisco, and its transmitter antenna is located atop Sutro Tower.

From its founding in 1949 until December 2001, KRON was affiliated full-time with NBC, however, since April 2010, KRON has an informal secondary affiliation with NBC, carrying network programs that are preempted by NBC O&O KNTV due to special programming. It is the only television station in the US to carry a seven-hour morning newscast, which airs from 4-11am."

-Wikipedia